NAND flash memory, as well as other types of non-volatile memories (“NVMs”), are commonly used for mass storage. For example, consumer electronics such as portable media players or cellular telephones often include raw flash memory or a flash card to store music, videos, and other media.
Non-volatile memories may include initial defects. Thus, tests are typically performed on these non-volatile memories during their manufacturing phase to ensure that the initial defects do not exceed a predetermined threshold. Those non-volatile memories that pass the test may be configured to avoid using the memory cells that have the initial defects. These non-volatile memories may then be shipped for use by an end user or for packaging into an electronic device that can then be used by an end user.
Non-volatile memories, however, may develop further defects over time, such as due to over-erasing blocks of the non-volatile memory. These additional defects may be handled using error correcting codes or bad block management.